Spamkiss reduces spam - drastically. And it does its work where spam arises, with the Spammer himself. It relieves those who now pay for spam - the provider and the recipient. The Spamkiss System carries out a Sender-Authentication before it delivers an email to the mailbox. This offers the decisive difference from the widespread use of filters, which essentially deal with filtering spam already mailed. It is the door for the mailbox, which finally enables the user to decide with whom he wants to communicate - and with whom not!